The use of geosynthetics in road construction. Geosynthetics in road construction. Application of geogrid Armiset-SL

Engineering practice in the field of road construction, including the strengthening of slopes and excavations, proves a low rate of design and technological solutions in this area. This is due to several reasons: the lack of lightweight types of structural reinforcement, and the need for industrialization of road structures, as well as a reduction involume of necessary work(construction, reconstruction, repair roadbed). One of constructive solutions is the applicationgeo synthetic materials, whichfor more than 50 years have been actively used in road construction throughout the whole of Europe. Geosyntheticmaterials help to increasesoil stability and roadmounds, provide protection against erosion, thereby preventing the process of suffusion. The use of geosynthetics increases the efficiency of technical and economic solutions in road construction. Currently, laboratory and field studies are underway to determine the effectiveness of the use of road geotextiles, which repeatedly prove the manufacturability of the material.

Study of the effectiveness of the use of materials

With the creation of a full-size model of the roadway on crushed stone base in clay soil it became possible to study the mechanism by which it provides the strengthening function of the roadway model under these conditions when a two-axle vehicle moves along it with a load on the rear new axle 9.1 t.

The most interesting data was obtained by creating the same level of road deformation as in the case of impact vehicle. In the part of the web that contains the geotextile, the level of deformation is lower and less pronounced within the entire area of ​​impact of the wheel. On the contrary, in that part of the roadway where geotextiles are not contained, the deformations were deeper.

Technical and economic advantages of permeable nonwoven fabric placed between the soil and the base of the roadway do not raise any doubts, however, very often when designing one has to face the problem of choosing the most suitable type material for specific tasks.

Density of road geotextile? What is the difference?

In general, it can be said that when exposed to the same load, the use of light materials (200-250 g / m²) provide a low tensile strength and high permeability, while the use of materials with a slightly higher density (300-400 g /m²) leads to an increase in tensile strength and a decrease in permeability.

The choice of density of the geosynthetic material depends on the purpose road construction. For example, in the construction of federal highways, it is recommended to use geotextiles with a density of more than 300 g/m2.

Construction and road reconstruction is an important branch of modern industry. Since highways are designed to be durable and function in in full, during their construction should be used the most efficient technologies and materials. Important role in this area today play geosynthetics. They are designed to reinforce the road structure, as a result of which performance characteristics canvases multiply. For example, the popularity of geogrid(http://www.td-geo.ru/materials/geosetka).

Application in construction

This material has a mesh structure and is extremely durable. Depending on the scope of application, grids for asphalt concrete and soil are distinguished. Geosynthetics the second type are used to strengthen the slopes of the railway track and coastline artificial reservoirs, the construction of temporary access roads, the strengthening of unstable soils before laying pavements, the prevention of landslides, etc. In addition to highways, the geogrid is also used in the construction of runways and hydraulic structures. Geogrid properties to a large extent also depend on the material from which they were made.

Currently, manufacturers supply the market with nets made of polyethylene, polypropylene, polyester, fiberglass, polyamide, polyester, and possibly other polymeric and synthetic materials. In addition, geogrids are uniaxial (oriented in one direction) and biaxial (oriented simultaneously in two directions).

Each of these options has its own advantages and almost no disadvantages. Geosynthetic basis of reinforcing material determines its physical and mechanical properties. For example, the geogrid is not subject to corrosion and is able to withstand any temperature fluctuations in the range from -40°C to +60°C. It does not rot from dampness, does not crack and is not of interest to rodents.

Technical features of use

Reinforcing fabrics laid in asphalt concrete are treated with a special compound that significantly increases adhesion. This makes the structure monolithic and more durable. Depending on the modification, the mesh cell size varies from 5 to 50 mm. Polymer reinforcement prevents the appearance of cracks, potholes, delaminations and other structural defects. Due to this, the quality indicators of roads are improving and the time interval between repair and restoration work is significantly increased.

Today, the introduction of new technologies in the road is extremely necessary. Huge streams of large-tonnage vehicles moving daily along federal highways make it clear what colossal loads the roadway is subjected to. Fortunately, geosynthetics allow not only to extend its life, but also to reduce financial investments in repair and construction projects. So, the economic benefits of using a geogrid are obvious.

Geosynthetics for road construction is an innovative building material based on polymers (polyethylene, polyamide, polypropylene, etc.), which has been widely used in Russia for the past 10 years. Its use provides high level design solutions and environmental requirements, and also increases the life of the roadway.

Functions of geosynthetics

The main functions that geosynthetic materials perform for road construction:

• Reinforcement (geogrids, geogrids). The material redistributes the weight load, thereby strengthening the roadway.
• Filtration (geocomposites, geotextiles). Composites and textiles allow water to seep through without moving into the base of the roadbed.
• Drainage (geocomposites, geogrids). Fitted to drain water.
• Strengthening the strength of asphalt concrete layers (geogrids, geogrids). Redistribution of tensile loads, mechanical effects.
• Prevention and control of soil erosion (geomats, geocells). The material slows down erosion, heaving and other soil deformations due to climatic influences.
• Strengthening of weak soil (geocomposites, geotextiles). Strengthening the bearing capacity of the soil base.
• Separation of fabric layers (geocomposites, geotextiles). Prevention of cake layers from caking.
• Waterproofing (geomembrane, geocomposition). Reduces the flow of liquid media to the subgrade.
• Protection against mechanical damage (geogrids, geomats, geotextiles).

Depending on the purpose of the material and individual features Soil geosynthetics can perform one or more functions.

Properties of geosynthetic materials for road construction

Geosynthetics have a number of unique properties:

• Resistance to chemicals, aggressive environments.
• Durability (the term of use reaches up to 100 years).
• resistance to high and low temperatures, medium differences.
• Low material consumption.

Reference. With a combination of versatility, durability and resilience, modern projects using geosynthetics for road construction can reduce the repair time by 2-3 times, reduce consumption building materials. In addition to solving a number of technical problems, geomaterials lead to a tangible economic effect!

Classification and types of geosynthetic materials

When choosing a geomaterial great importance has its type, which is selected based on the assigned construction tasks.

Depending on the function, materials can be of several types of permeability: gas-tight, draining, filtering, insulating.

According to the structure, geosynthetic materials are divided into the following types:

• geotextile;
• geogrids;
• geogrids;
• geocomposites;
• geomats;
• geocameras;
• geomembranes.

Geogrids, geogrids

This is a rolled or modular mesh material made of synthetic or polymer threads. It is made on the basis of polyamide, polyethylene, polyester, polypropylene, fiberglass, etc.

Geogrids are larger than geogrids in thickness and cell size. They are actively used to prevent erosion of retaining walls, strengthen ravines, road slopes, in the arrangement of automobile, railways on weak soils. The material also has good reinforcing properties. It is used in the foundations of the roadbed, load-bearing platforms, as well as to strengthen the abutments of bridges. As a cell filler, concrete of the minimum grade M200, crushed stone, sand, and soil are used. Maximum effect is achieved due to the adhesion of the cells with the filler. Installation temperature ranges from -40 to +60 degrees. The cell diagonal can be 0.2m, 0.3m, 0.4m. Dimensions range from 2 to 3m (width), from 5.5 to 12m (height). Module thickness from 0.05 to 0.2m. Tape thickness min 1.5 mm. The load of the weld at break is from 50% of the strength of the tape.

Geogrid is durable yet lightweight flexible material. It is produced in rolls. The main purpose of the grid: the exclusion of interpenetration of layers, reinforcement, alignment and strengthening. The geomaterial is laid in the ground or asphalt concrete pavements, including the upper asphalt layers. Mesh size from 2.5 to 40 mm. Service life over 50 years.

According to the method of forming the weaving of the grid, a two-axle and one-axle grid is distinguished. Single-axle geosynthetics involves balancing a high long-term load in one direction. She has flat view with long narrow sections. The double-axle geogrid distributes loads in the transverse and longitudinal direction. Has cells square shape with rigid node connections.

Geotextile

Geotextile is a roll (sometimes sheet) material that is made from polypropylene or polyester. High flexibility, strength characteristics, water resistance allow it to be used in a variety of construction works.

In road construction, the material serves to filter moisture, not mixing the soil with crushed stone, which prevents the road surface from deforming. Its use reduces the appearance of cracks by 3 times. An important criterion in the choice of geotextile is the density.

In road construction, geotextiles are used with a density of:

• 200-300 g/m2. It is used in the construction of car parks, roads for small vehicles or light traffic.
• 300-400 g/m2. For roads with high load ( freight transport, high traffic intensity).
• 450-500 g/m2. The material is used for temporary roads as a separator between crushed stone layers.

According to the texture and method of weaving the threads of the material are distinguished:

• Non-woven geotextile. Arrangement of fibers without system weave. The fabric is impregnated special formulations. The material stretches well, but has low strength. Reduces road loads.
• Woven geotextile. In a woven material, the fibers are intertwined, as in a fabric, perpendicular to each other. In this case, two or more strips of threads are used. Woven is more durable and is used in pavement layers. It significantly reduces the load on the roadway.
• Knitted. It consists of fibers connected by a special scheme. Used for media distribution, drainage.

Geocomposites

A geocomposite is a two-, three- and multi-layer structure of geomaterial compositions that combines all the characteristics and properties of the layers used. The main task of the material is drainage and filtration. The material is used in the arrangement of vertical edge drainage of highways, drainage of retaining walls.

The following combinations are found in the construction market:

• Geotextile geogrid. For example, a combination nonwoven filter and grids with diamond-shaped cells made from compositions of low and high pressure polyethylene;
• Geomembrane-geotextile. In this case, the geotextile acts as a filter, and the geomembrane acts as a waterproofing layer and provides a gap for water to flow out.

Main technical parameters material are layer thickness, density.

Geomembranes

Membranes are a continuous, moisture-resistant synthetic fabric for insulating layers. Membranes for road construction are distinguished by their polyethylene composition high strength with a layer thickness of 1 to 4 mm. The main difference between membranes and other geosynthetics is its tensile strength, which reaches over 600%. The material is produced in rolls or sheets of many dimensions, which allows you to arrange flooring with minimal joints.

Advice! For road construction, a profiled geomembrane is applicable. With a high level of web embankment, it is better to lay the membrane at a depth of 0.5 to 1 m from the edge.

Scope of application in road construction - silty soils, soils with underground rivers, wet climatic zones. The membrane layer eliminates frost heaving, rupture of asphalt layers. Places of laying can be tunnels, bridges, bridge supports, especially wet sections of roads.

Reference. For best effect manufacturers recommend using geomembranes paired with a geogrid, grid or geocomposite.

Geomats

Geomat is lightweight material three-dimensional fibrous structure with a cellular structure, providing fixation of the root system of plants and trees. Unlike the grid, its cells are very small and arranged in a chaotic manner. Its shape allows the roots of plants and trees to intertwine with their own fibers. Used to prevent and reduce soil erosion.

The material is produced in mats, overlapped in the foundations of retaining walls, slopes and slopes.

Geocameras

Geochambers are applicable in the field of innovative construction, for the construction of hydraulic structures. They are used as a form for filling with loose and medium fraction materials. They differ in height and cell size. The material well passes moisture, water, increases the resistance of the structure to deformation, is not subject to destruction under the influence of heat, frost, ultraviolet rays.

The use of geosynthetic materials in road construction in Russia is actively growing. A significant increase in the range and assortment provides a high level of solutions to various design problems, which gives impetus to improving the quality of the canvas and reducing the use of natural resources.

Road pavements are engineering structures located at the interface between two media (air-soil), which manifests the specificity of their work and operational maintenance. As you know, the ability of pavement to perceive loads directly depends on the state of the surface layers of the soil, which is not constant in time due to seasonal soaking, drying, freezing and thawing under the influence of changes in meteorological factors - precipitation and air temperature. The range of changes in the bearing properties of the surface layer of soils during the year is very significant, especially in areas with frosty winter: from a solid, practically not deformed frozen surface under the wheels, to a weak water-saturated during spring thawing. In addition, sometimes it is necessary to design and build roads on heavy clay, subsidence, technogenic soils, in areas with complex hydrogeological and climatic conditions, in cramped conditions.

In all these cases, builders have to carry out road survey and implement measures to improve physical and mechanical properties soils, which include soil strengthening with cement, lime, binders, soil compaction with special high-performance machines, regulation of the water regime of foundation soils using a drainage device.

Variety of soil and climatic conditions of the construction areas, various operating conditions of individual structural layers, a significant number of factors affecting the coating in combination with natural dispersion quality characteristics of the materials used require a deep analysis when choosing and justifying the appropriate method for improving the physical and mechanical properties of soils.

All this predetermines the need to develop and improve a variety of methods for surveying roads and pavements, each of which could be the most appropriate.

Analysis of methods used in domestic and world practice to increase bearing capacity made it possible to single out promising ones from among them, among which the most effective for solving the above tasks and the least developed in our country are car roads using geosynthetics.

Geosynthetics- a class of polymeric building materials that themselves or as part of structures on soils can perform the functions of reinforcement, filtration, separation and drainage and have qualitatively new properties compared to traditional building materials, namely:

• high strength;
• chemical resistance;
• durability;
• high temperature resistance;
• low material consumption, etc.

By structure, geosynthetic materials are divided into:

• geotextile
• geogrids
• geogrids
• geocomposites
• geomats
• geocameras
• geomembranes

According to the permeability, geosynthetic materials can be classified into 4 categories - insulating moisture-proof, gas-tight, filtering and drainage.

All of them, in turn, are subdivided according to types into loose, rolled materials and geofoams.

In terms of "load / elongation" into inextensible, extensible and superextensible.

The use of geosynthetic materials for road design and the design of pavement pavements is based on the introduction of a synthetic element into the design. Depending on the purpose of the structure, the design features and the type of material, geosynthetics can perform either one function or several functions at the same time. The most well-known functions of geosynthetics are summarized in the table.

Abroad, there is already sufficient experience in the use of synthetic materials in road design and construction.

Development chemical industry, a significant expansion of the range of synthetic and composite materials, simplification of technology and improvement of their physical and mechanical characteristics leads to a significant reduction in the cost of production of the designed roads.

Geosynthetic materials are promising building materials, the use of which in the design of roads provides a high level of design solutions, construction technologies, production culture and compliance with environmental requirements for facilities under construction.

The experience of using "reinforced soil" abroad is huge. There are many theoretical and experimental studies of scientists from different countries devoted to the mechanics of reinforced soil. Therefore, scientific research in the field of application of geosynthetic materials in our country should be supplemented by active introduction into the practice of designing and building roads.

They are made using the following materials:

• Polyester (PET).
• Basalt roving.
• Polypropylene (PP).
• Glass roving.
• polyvinyl alcohol (PVA) and so on.

Their use allows to significantly increase the strength and service life of various structures.

Modern Russian market geosynthetics, where PTC "United Resources" occupies one of the leading positions, is developing more and more actively. All more construction organizations introduce modern technologies based on the application of the considered materials. And they have already appreciated all the advantages of the widespread use of geosynthetics.

Geosynthetics for road repair and construction

Geosynthetics in construction allows not only to increase the durability of structures, but also to simplify and reduce the cost of manufacturing process. Such material will be an excellent basis for any construction site, because it has:

• Excellent resistance to environmental conditions.
• Excellent durability to break.
• Resistant even to aggressive chemical compounds.

Add to this a light weight that simplifies transportation and a relatively low cost, and the economic benefit becomes obvious.

Geosynthetics has been used in road construction in the world since the late 1960s. In Russia, such technologies were initially reluctant to take root due to the high cost of materials, which until recently were produced only in Europe. But in last years thanks to the launch domestic production, they have become very actively used in our country.

Geosynthetics buy

The geosynthetics offered by us (the price on our website is indicated directly from the manufacturer, Makhina-TST LLC) meets all the necessary state standards and has been certified in Germany. In the catalog you will find:

• ASPHALTEX geogrids and DUALTEX geocomposites, with which asphalt concrete layers are reinforced ().
• GRUNTEX and STRADEX geogrids for reinforcing the lower layers of pavement ().
• DACRON GEO non-woven geotextile used for separating different layers pavement ().
• Geotextile high-strength woven STABBUDTEX, used for reinforcing fragile bases () and other names.

We guarantee that the cost of geosynthetics from our organization is very democratic!